Velodyne Subwoofer

Selling a Velodyne subwoofer. It's black and in used condition. It has some scratches and signs of wear but still sounds great! ADVENT Sunfire Technologies AV550S Subwoofer. works and in good condition Has anyone heard of this? How much is it worth? The Advent AV550S is the result of a unique collaboration between BOB CARVER and Sunfire Technologies. If you are looking for deep, floor-shaking bass, you will love this. It has a 15" woofer and just about every type of input imaginable, including RCA, speaker, and LFE. It also has gain, crossover, and phase controls to get the perfect sound for movies, games, and CDs.